1. Field of the Invention
The present invention relates to a work support apparatus for properly teaching the operator an assembling procedure, parts to be used, and the like through a monitor or the like in a process of manufacturing a product. More particularly, the invention relates to a work support apparatus for verifying execution of pickup of a part from a parts shelf in which a plurality of parts storage boxes are housed by sensing a hand of the operator reaching a parts storage box by using a photoelectric sensor.
2. Description of the Prior Art
Generally, assembly, processing, inspection, and the like of products by the operator in an FA manufacture site are performed in a dedicated work space. In the work space, usually, a work table, a parts shelf in which a plurality of parts storage boxes are housed, and a jig shelf in which a plurality of jig storage boxes are housed are provided. Usually, a work instruction sheet in which parts and jigs necessary in work processes, modes of attaching parts, and the like are shown by sentences and drawings is distributed to each operator and the operator performs an operation in accordance with the work instruction sheet. However, it is not easy to form a work instruction sheet which is easily understood even by an operator who does not have enough experience. In a work performed by the operator while seeing the work instruction sheet, the level of skill and capability of each person are noticeably reflected in work speed, so that various problems occur such that work speed varies and a production line is delayed. Consequently, a work support apparatus (refer to, for example, Japanese Unexamined Patent Publication No. Hei 10-301472) and a work support apparatus (refer to, for example, Japanese Unexamined Patent Publication No. Hei 5-42461) have been proposed. The former work support apparatus properly teaches the operator an assembly procedure via a monitor or the like in accordance with inputs from various sensors for sensing a work (event) of an operator at a site, switches, timers, or the like. In the latter work support apparatus, a plurality of parts storage boxes are prepared. An indicator such as a lamp provided for a parts storage box storing parts necessary for each work is illuminated. A part picked up by the operator is detected by a photoelectric sensor provided for each parts storage box. If the operator picks up a part from parts storage boxes other than the parts storage box to be selected, a warning device operates.
By also combining the known techniques, a work support apparatus capable of properly teaching the operator an assembly procedure through a monitor, an indicator or the like, instructing pickup of a part from a parts storage box, and verifying the execution can be also realized.
The work support apparatus using the photoelectric sensor has, however, the following problems.    (1) A photoelectric sensor for sensing that a part is taken out from a parts storage box is disposed for each parts storage box. At the time of changeover, it is necessary to prepare parts storage boxes corresponding to different parts or replace parts in a parts storage box. In a site where production of small volumes of a wide variety of products is required, if a number of parts storage boxes according to the number of kinds are prepared, photoelectric sensors according to the number become necessary. It causes problems such that the cost increases and wiring requires much time and labor. When parts in the parts storage box are interchanged, problems occur such that the work efficiency deteriorates and, in addition, the risk that different kinds of parts mix increases.    (2) Further, in a site where production of small volumes of a wide variety of products is required, the sizes and kinds of the parts are various. Consequently, it is ideal to prepare parts storage boxes of various sizes. However, since the photoelectric sensor is disposed for each of the parts storage boxes, if photoelectric sensors of various sizes corresponding to the parts storage boxes of various sizes are prepared, the cost increases substantially. Due to this, hitherto, parts storage boxes of the same size are used irrespective of the sizes of parts. In other words, it is difficult to provide flexibility to layout of the parts storage boxes. It causes inconvenience in a changeover.